MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY DECEMBER, 2008 (For general comments about the nature of these summaries, as well as information on how to download the tabular cyclone track files, see the Author's Note at the end of this summary.) ************************************************************************* DECEMBER HIGHLIGHTS --> Finally, after three months, a typhoon develops --> Some more Indian Ocean activity, both north and south ************************************************************************* WIKIPEDIA TROPICAL CYCLONE REPORTS Short reports with satellite pictures and small-scale maps for all tropical cyclones may be found at the following links: For some storms more detailed reports have been prepared. In those cases I will include the specific links in the reports for the applicable tropical cyclones. ************************************************************************* !!!!!!!!!! EXTRA FEATURE !!!!!!!!!! A REVIEW OF THE 2008 TROPICAL CYCLONE SEASON FOR THE NORTHERN HEMISPHERE Following is a tabular summary of all the tropical depressions, tropical storms, hurricanes, and typhoons which occurred in the Northern Hemisphere between 1 January and 31 December 2008, as reported in the Monthly Global Tropical Cyclone Summaries prepared by the author. (1) Number - this is the sequential cyclone number assigned by either TPC/NHC, CPHC in Honolulu, or JTWC. If neither of these agencies issued any warnings, no number will be given. (2) Name - the name (if any) assigned by either TPC/NHC, CPHC, IMD, or JMA (and PAGASA for Western North Pacific systems in their area of warning responsibility). (3) Dates - range of dates for which tracking information for the cyclone is available in the Global Tropical Cyclone Tracks files prepared by the author. (4) Pressure - Lowest central pressure (either estimated or recorded) during the lifetime of the cyclone. For Atlantic and Northeastern Pacific systems these will be the values reported in operational advisories from TPC/NHC or CPHC. For Northwest Pacific systems the central pressure estimates are taken from advisories issued by the Japanese Meteorological Agency. An asterisk (*) following the pressure indicates the reading was an actual measured pressure normally obtained by a drop- sonde released during an aerial reconnaissance flight. Central pressure is given in millibars, which is numerically equivalent to hectopascals. (5) MSW - maximum 1-minute average sustained windspeed in knots. For the Northwestern Pacific and North Indian Ocean basins, these will be the highest value assigned operationally by JTWC. For the Atlantic and Northeastern Pacific basins, the MSW values are taken from the official tropical cyclone reports prepared by the TPC/NHC Hurricane Specialists and which are available on TPC/NHC's website: . (6) Basins - tropical cyclone basins where the cyclone tracked during its life: ATL - North Atlantic, Gulf of Mexico, Caribbean Sea NEP - North Pacific east of Longitude 180 NWP - North Pacific west of Longitude 180 (including South China Sea) NIO - Bay of Bengal and Arabian Sea For tropical systems in the NWP basin, two additional columns of information are given: (1) The tropical storm serial number assigned by the Japanese Meteorological Agency to tropical depressions which are deemed to have reached tropical storm intensity. This does not always agree with JTWC's assessment. (2) An estimate of the maximum 10-minute average sustained wind. The value given represents the highest 10-min avg MSW assigned by any agency. If from any warning center other than JMA, a numbered note below identifies which center's value is given. A number in parentheses (e.g. (1) ) following an entry refers to a note following the entries for the given basin. A separate table is given for each of the four Northern Hemisphere basins. ========================================================================= ATLANTIC BASIN NUM NAME DATES CENT PRS MSW BASIN (mb) (kts) ------------------------------------------------------------------------- 01 Arthur 31 May-02 Jun 1004 * 40 ATL 02 Bertha 03-20 Jul 952 110 ATL 03 Cristobal 19-24 Jul 998 * 55 ATL 04 Dolly 20-28 Jul 963 * 85 ATL 05 Edouard 03-07 Aug 996 * 55 ATL 06 Fay 15-28 Aug 986 * 60 ATL 07 Gustav 25 Aug-04 Sep 941 * 130 ATL 08 Hanna 28 Aug-12 Sep 977 * 75 ATL 09 Ike 01-15 Sep 935 125 ATL 10 Josephine 02-06 Sep 994 55 ATL -- ----- 23-26 Sep 990 55 ATL (1) 11 Kyle 25-29 Sep 984 75 ATL 12 Laura 26 Sep-05 Oct 994 50 ATL (2) 13 Marco 06-08 Oct 998 * 55 ATL 14 Nana 12-14 Oct 1004 35 ATL 15 Omar 13-21 Oct 958 * 115 ATL 16 ----- 14-16 Oct 1004 25 ATL 17 Paloma 05-10 Nov 944 * 125 ATL NOTES: (1) System was a frontal hybrid which developed pronounced subtropical cyclone characteristics before moving onshore in the Carolinas. Convection was quite well-organized but surface data showed the LOW to still have a frontal structure. In its earlier stages, as an extratropical storm, the system had produced hurricane-force winds. (2) This system was named as a subtropical storm and later acquired tropical cyclone characteristics. ========================================================================= NORTHEAST PACFICIC BASIN NUM NAME DATES CENT PRS MSW BASIN (mb) (kts) ------------------------------------------------------------------------- 01E Alma 29-31 May 994 55 NEP 02E Boris 27 Jun-04 Jul 985 70 NEP 03E Cristina 27 Jun-01 Jul 1000 45 NEP 04E Douglas 02-04 Jul 1003 35 NEP 05E ----- 05-07 Jul 1005 30 NEP 06E Elida 12-19 Jul 970 90 NEP 07E Fausto 16-22 Jul 977 80 NEP 08E Genevieve 21-27 Jul 987 65 NEP 09E Hernan 06-13 Aug 956 105 NEP 01C Kika 07-12 Aug 1007 35 NEP 10E Iselle 13-17 Aug 999 45 NEP 11E Julio 23-26 Aug 998 45 NEP 12E Karina 02-03 Sep 1000 35 NEP 13E Lowell 07-12 Sep 998 45 NEP 14E Marie 01-06 Oct 984 70 NEP 15E Norbert 04-12 Oct 945 115 NEP 16E Odile 08-12 Oct 997 50 NEP 17E ----- 23-24 Oct 1008 30 NEP 18E Polo 02-05 Nov 1003 40 NEP ========================================================================= NORTHWEST PACFICIC BASIN JTWC NAME(S) JMA DATES CENT MSW MSW BASIN NUM TROP STM PRS 1-MIN 10-MIN NUM (mb) (kts) (kts) ------------------------------------------------------------------------- 01W ----- ---- 13-18 Jan 1004 35 30 NWP 02W Neoguri/Ambo 0801 13-19 Apr 960 95 80 NWP 03W Rammasun/ (1) 0802 06-13 May 915 135 105 NWP 04W Matmo/Dindo 0803 14-17 May 994 40 45 NWP 05W Halong/Cosme 0804 13-23 May 975 70 60 NWP 06W Nakri/Enteng 0805 26 May-09 Jun 930 125 105 NWP 07W Fengshen/Frank 0806 17-27 Jun 945 95 90 NWP --- Gener ---- 04-07 Jul 1000 -- 30 NWP (2) 08W Kalmaegi/Helen 0807 12-21 Jul 960 90 75 NWP --- ----- ---- 13-15 Jul 1004 -- 30 NWP (3) 09W Fung-wong/Igme 0808 23-30 Jul 960 95 85 NWP 10W Kammuri/Julian 0809 03-08 Aug 975 50 50 NWP --- Phanfone 0810 09-11 Aug 995 -- 40 NWP (4) 11W ----- ---- 12-15 Aug 1000 30 25 NWP 12W Vongfong 0811 14-18 Aug 992 50 40 NWP 13W Nuri/Karen 0812 17-23 Aug 955 95 75 NWP 14W Lawin ---- 25-28 Aug 1000 30 30 NWP (2) 15W Sinlaku/Marce 0813 08-22 Sep 935 125 90 NWP 16W ----- ---- 09-12 Sep 1002 35 30 NWP 17W ----- ---- 13-17 Sep 1010 30 25 NWP 18W Hagupit/Nina 0814 17-25 Sep 935 120 90 NWP 19W Jangmi/Ofel 0815 23 Sep-02 Oct 901 * 145 115 NWP 20W Mekkhala 0816 27-30 Sep 980 55 50 NWP 21W Higos/Pablo 0817 29 Sep-06 Oct 998 45 40 NWP 22W ----- ---- 13-15 Oct 1006 35 30 NWP 23W Bavi 0818 18-25 Oct 992 45 45 NWP 24W Maysak/ (5) 0819 06-14 Nov 985 60 50 NWP 25W Haishen 0820 15-21 Nov 1006 40 35 NWP 26W Noul/Tonyo 0821 15-18 Nov 996 40 40 NWP 27W Dolphin/Ulysses 0822 02-19 Dec 970 90 65 NWP NOTES: (1) The name assigned to Rammasun by PAGASA was Butchoy. (2) This system was named by PAGASA. (3) Classified as a tropical depression by JMA only. (4) This system was treated as a tropical cyclone by JMA only. (5) Two PAGASA names were applied to various stages in the life of this system: Quinta and Siony. ========================================================================= NORTH INDIAN OCEAN BASIN NUM NAME DATES CENT PRS MSW BASIN (mb) (kts) ------------------------------------------------------------------------- 01B Nargis 27 Apr-03 May --- 115 NIO --- ----- 05-07 Jun --- 30 NIO 02B ----- 15-19 Sep 993 40 NIO 03B ----- 19-23 Oct 1000 35 NIO 04B Rashmi 25-27 Oct 1000 45 NIO (1) 05B Khai Muk 13-16 Nov 998 45 NIO 06B Nisha 25-28 Nov 1000 50 NIO (1) 07B ----- 04-07 Dec --- 35 NIO NOTES: (1) The 1000-mb CP value given above was not for the time of maximum intensity. ************************************************************************** ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for December: No tropical cyclones ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for December: No tropical cyclones ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for December: 1 tropical depression ** 1 typhoon ** - treated as a tropical depression by JMA only Sources of Information ---------------------- Most of the information presented below is based upon tropical cyclone warnings and significant tropical weather outlooks issued by the Joint Typhoon Warning Center of the U. S. Air Force and Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion tropical cyclone tracks file, I normally annotate track coordinates from some of the various Asian warning centers when their center positions differ from JTWC's by usually 40-50 nm or more. All references to sustained winds imply a 1-minute averaging period unless otherwise noted. Michael V. Padua of Naga City in the Philippines, owner of the Typhoon 2000 website, normally sends me cyclone tracks based upon warnings issued by the Japanese Meteorological Agency (JMA) and the Philippines' Atmospheric, Geophysical & Astronomical Services Administration (PAGASA). A very special thanks to Michael for the assistance he so reliably provides. In the title line for each storm I have referenced all the cyclone names/numbers I have available: JTWC's depression number, the JMA-assigned name (if any), JMA's tropical storm numeric designator, and PAGASA's name for systems forming in or passing through their area of warning responsibility. Northwest Pacific Tropical Activity for December ------------------------------------------------ After nearly three months without a typhoon, the Northwest Pacific ended the year on a more normal note with Typhoon Dolphin tracking northward east of the Philippines. What was unusual about Dolphin was its origin and track. The system began life as an extratropical gale near Iwo Jima, described a huge oval-shaped loop taking in a large chunk of the WESTPAC, evolving into a subtropical and then tropical cyclone, and finally ending up once more as an extratropical LOW near Iwo Jima. A report on Dolphin follows. JMA classified a low-pressure system in the southern South China Sea west of northern Borneo as a minor tropical depression on 2 December, but late in the day downgraded it to a low-pressure area. No track was given for this system in the companion cyclone tracks file. TYPHOON DOLPHIN (TC-27W / TY 0822 / ULYSSES) 2 - 19 December ------------------------------------------------ Dolphin: contributed by Hong Kong, was selected to represent the Chinese while dolphins which live in Hong Kong waters; also, the dolphin is a mascot for Hong Kong Typhoon Dolphin provided a very unusual and interesting, even if not spectacular, ending to the rather quieter-than-normal 2008 typhoon season. As a typhoon it was not particularly notable, but its origin and pre-tropical cyclone phase were quite out of the ordinary. As early as 2 December a High Seas Warning issued by JMA noted that a new extra- tropical LOW had formed near 25N/143E, or roughly 100 nm east-northeast of Iwo To, or over 650 nm south-southeast of Tokyo. The system moved rapidly east-northeastward and intensified, reaching an intensity of 60 kts by 03/0600 UTC. The extratropical storm had reached a position near 31N/158E, or about 850 nm northwest of Wake Island, by 0600 UTC on 4 December. After this the storm began to slowly weaken and its track began to bend east-southeastward, gradually curving more in a southward direction. At 0000 UTC 7 December the system reached the easternmost point of its trajectory about 375 nm east-northeast of Wake Island, or near 21N/173E. JMA still forecast the winds to be 50 kts, and although I have no information regarding its nature, it seems likely that the system by this time had taken on some hybrid/subtropical characteristics. The LOW quickly curved to a west-southwesterly track which carried it deeper into the tropics. JMA classified the system as a weak tropical depression at 0000 UTC 8 December while located about 275 nm southeast of Wake Island. The classification was lowered to 'low pressure area' at 09/0000 UTC, but raised back to tropical depression status 24 hours later. A STWO issued by JTWC at 0600 UTC 9 December mentioned the system, which was then located about 440 nm northwest of Kwajalein Atoll. At this time things didn't look too good for development. While AMSU data showed a pronounced warm core, convection had waned and upper-level support was dreadful with 30-40 kts of vertical shear over the region. A 09/1954 UTC QuikScat pass showed that the LLCC had continued to break down into a wave, and early on the 10th QuikScat data still showed no surface westerly winds. However, shortly after the 10/0600 UTC STWO was issued, things turned around. A circulation was shown to be rapidly consolidating and warnings were initiated on Tropical Depression 27W at 10/1200 UTC, placing the center about 360 nm east of Guam with 25-kt winds. The MSW was upped to 30 kts at 10/1800 UTC as TD-27W zipped westward at around 17-18 kts. The depression's center passed about 53 nm south of Guam around 0900 UTC 11 December. At the same time JMA upped the winds to 30 kts. JTWC upgraded the system to tropical storm status at 11/1800 UTC with the center estimated to be about 285 nm northeast of Yap. JMA followed suit 12 hours later, naming the system Tropical Storm Dolphin. Interestingly, at the time of JTWC's upgrade, the storm was forecast to hang on to tropical storm intensity for 24 hours then slowly dissipate. This, of course, did not happen, although it took Dolphin three days to reach typhoon intensity. The newly-christened storm slowly increased in intensity during the next 24 hours as it continued westward, reaching 55 kts by 13/0000 UTC (45 kts per JMA). Dolphin's intensity remained steady at 55-60 kts for the next couple of days as it continued to move westward but at a decelerating pace. (As the system entered PAGASA's AOR around 13/1200 UTC, it was given the local name Ulysses.) JTWC upgraded Dolphin to typhoon status at 15/0000 UTC with the center located approximately 535 nm east of Manila. Typhoon Dolphin/Ulysses was tracking west-northwestward at 6 kts as it moved toward a weakness in the subtropical ridge induced by an approaching mid-latitude trough. By 1200 UTC the cyclone had turned to a northerly course. It was at this time that JMA upgraded Dolphin to typhoon strength, and also the time of JTWC's estimated peak intensity of 90 kts, based on satellite intensity estimates of 77 and 90 kts. Dolphin was capped by a mesoscale anti- cyclone which had enhanced outflow as well as helped to buffer the typhoon from strong vertical shear associated with the approaching upper-level mid-latitude trough. Dolphin's estimated MSW dropped slightly to 85 kts and remained there for 18 hours before more rapid weakening set in. JTWC reduced Dolphin to minimal typhoon status at 16/1800 UTC with the storm now moving north-northeastward. (JMA's 10-min avg MSW estimate for Dolphin never exceeded 65 kts, and that agency classified Dolphin as a typhoon for only 24 hours.) Typhoon Dolphin continued to weaken as it accelerated northeastward. It weakened to a tropical storm at 17/0600 UTC, and both JTWC and JMA declared the former extratropical/subtropical/tropical cyclone to be extratropical once more at 18/1200 UTC. Dolphin's remnants at this time were located about 40 nm east of Iwo To, and the final JMA reference to the system at 19/0000 UTC placed the weak center at 24N/145E, or only about 125 nm from its point of origin. During its entire life cycle, this remarkable system in essence described a huge loop taking in much of the tropical and subtropical Western North Pacific. Large swells affected many islands through the Pacific. As far away as Papua New Guinea huge waves smashed into dozens of villages and towns, rendering more than 400 people homeless. Significant wave heights of 2-3 metres were occurring around New Britain. According to Roger Edson, it was the intensification of the subtropical LOW as it moved from 30N/160E to around 20N/175E that 'triggered' the big winds and hence the big waves. It was not the resultant tropical LOW (later TD-27W) which were responsible for the waves, but the 60+ kt winds over a 300-mile wide area north of the subtropical LOW. Following are a couple of links to information concerning the Papua New Guinea damage: Sadly, there was significant loss of life associated with Typhoon Dolphin. According to the Wikipedia report, the M/Bca Mae Jan was a cargo passenger ship which sank on 14 December due to rough seas caused by the typhoon. At the time of its sinking the ship was carrying 98 people. Of these, 47 were known dead, six persons were reported missing, and 46 people survived. The Wikipedia report on Typhoon Dolphin may be accessed at the following URL: (Report written by Gary Padgett) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for December: 1 tropical cyclone ** ** - treated as a deep depression by IMD Sources of Information ---------------------- Most of the information presented below is based upon tropical cyclone warnings and significant tropical weather outlooks issued by the Joint Typhoon Warning Center of the U. S. Air Force and Navy (JTWC), located at Pearl Harbor, Hawaii. Occasionally some information may be gleaned from the daily tropical weather outlooks and other bulletins issued by the Indian Meteorological Department (IMD), which is the World Meteorological Organization's Regional Specialised Meteorological Centre (RSMC) for the basin. The reported maximum sustained winds (MSW) are based on a 1-minute averaging period, which is used by all U. S. civilian and military weather services for tropical cyclone warnings. For synoptic observations in the North Indian Ocean region, both 10-minute and 3-minute average winds are employed, but IMD makes no attempt to modify the Dvorak scale for estimating tropical cyclone intensity; hence, a 1-minute average MSW is implied. In the North Indian Ocean basin JTWC usually does not initiate warnings until a system has become well-organized and likely to attain tropical storm status within 48 hours. TROPICAL CYCLONE (TC-07B) 4 - 7 December ------------------------------------ Tropical Cyclone 07B was a rather far-traveled but weak tropical system which moved from the central Bay of Bengal westward at a low latitude and made landfall in Sri Lanka as a weak depression. An area of convection developed on 1 December about 800 nm east-southeast of Colombo, Sri Lanka. Limited deep convection was loosely rotating around a broad and poorly-defined LLCC. Vertical shear was low and the system had favorable diffluence aloft. The next day JTWC upgraded the potential for development to 'fair' as deep convection was beginning to wrap into an elongated but consolidating LLCC. The system by this time was centered about 685 nm east of Colombo. JTWC issued a TCFA at 2230 UTC on 3 December, followed by the first warning on TC-07B at 04/0000 UTC. This warning placed the center about 615 nm east of Colombo, or about 500 nm east of the eastern coast of Sri Lanka. The initial warning intensity was 30 kts, and TC-07B was tracking slightly north of due west at 5 kts. IMD classified the system as a depression at 04/0300 UTC. The system changed little in intensity over the next couple of days as it tracked westward. IMD upgraded it to deep depression status at 05/0000 UTC, and JTWC upped the winds to 35 kts at 06/0000 UTC when the center located approximately 360 nm east-northeast of Colombo. The LLCC was well-defined but partially-exposed. JTWC maintained TC-07B as a minimal tropical storm for 24 hours, then downgraded it to 25 kts and issued their final warning at 07/0000 UTC. A fully-exposed LLCC was sheared about 95 nm east of cycling, disorganized deep convection. According to an IMD outlook, by 07/1500 UTC the depression had moved inland into Sri Lanka and weakened into a well-marked low-pressure area. The residual LOW continued westward into the southeastern Arabian Sea but did not regenerate. IMD never classified this system above the deep depression stage; hence, no name was assigned. There are no reports of damage or casualties resulting from TC-07B. (Report written by Gary Padgett) ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for December: 1 severe tropical storm Sources of Information ---------------------- The primary sources of tracking and intensity information for Southwest Indian Ocean tropical cyclones are the warnings issued by the Tropical Cyclone Warning Centre on La Reunion Island, part of Meteo France (MFR), and the Regional Specialised Meteorological Centre for the basin. However, tropical cyclones in this region are named by the Sub-regional Tropical Cyclone Advisory Centres in Mauritius and Madagascar with longitude 55E being the demarcation line between their respective areas of naming responsibility. The La Reunion centre only advises these agencies regarding the intensity of tropical systems. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from MFR's coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. TROPICAL STORM CINDA (MFR-04 / TC-04S) 15 - 21 December ---------------------------------------- Cinda: contributed by Mozambique The first reference to the disturbance which ultimately developed into Severe Tropical Storm Cinda seems to have been in a STWO issued by JTWC at 1200 UTC on 13 December. An area of convection was persisting approximately 290 nm southeast of Diego Garcia. A LLCC had begun to rapidly consolidate with deep convection beginning to wrap into the center along the southern periphery. Vertical wind shear was low and JTWC assessed the development potential to be 'fair'. I do not have available the STWOs for 14 and 15 December, but apparently the rapid consolidation seen on the 13th was arrested. At 16/1800 UTC the potential for development was still assessed as 'fair'. The disturbance had migrated westward and by this time was located about 310 nm west- southwest of Diego Garcia. In the meantime, MFR had initiated bulletins on Tropical Disturbance 04 at 1200 UTC 15 December and 10-min mean winds were estimated at 25 kts with 30-kt winds occurring locally in the southern semicircle. Late on the 16th the disturbance began to intensify and MFR upgraded the classification to tropical depression status at 17/0000 UTC. At the same time JTWC issued their first warning on TC-04S, located about 370 nm west-southwest of Diego Garcia. Deep convection had developed over a tightly-wrapped LLCC, and Dvorak numbers were ranging from T2.0 to T2.5. After this spurt of strengthening, however, the intensity remained static for another 24 hours or so as the system continued to move west-southwestward across the South Indian Ocean. Late on the 17th TC-04S began to undergo another round of intensification. This led to Mauritius naming the system Tropical Storm Cinda at 0000 UTC 18 December. Six hours later Cinda reached its peak intensity of 50 kts (per MFR) while located about 450 nm southwest of Diego Garcia. (JTWC's peak 1-min avg MSW was 55 kts--in good agreement.) Around the time that Cinda reached its peak intensity its track took a southward turn. The storm also began to weaken as vertical shear increased. The winds had decreased to 40 kts by 19/0000 UTC but remained pegged there for a day and a half as Cinda returned to a more west-southwesterly course. MFR downgraded the tropical storm to a depression at 20/1200 UTC and to a tropical disturbance six hours later. JTWC issued their final warning on Cinda at 21/0000 UTC, placing the center about 480 nm northeast of Reunion Island, and MFR issued their final bulletin on ex-Cinda six hours later. No damage or casualties are known to have resulted from Tropical Storm Cinda. (Report written by Gary Padgett) ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for December: 1 severe tropical cyclone (intense) Sources of Information ---------------------- The primary sources of tracking and intensity information for Northwest Australia/Southeast Indian Ocean tropical cyclones are the warnings and advices issued by the Tropical Cyclone Warning Centres at Perth, Western Australia, Darwin, Northern Territory, and less frequently, by the centre at Jakarta, Indonesia. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from the Australian centres' coor- dinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. SEVERE TROPICAL CYCLONE BILLY (TC-05S) 17 - 29 December ------------------------------------------------- An area of convection developed and persisted on 16 December roughly 200 nm west-northwest of Darwin, Northern Territory, Australia. Weak convective banding was beginning to develop around a LLCC in the presence of low vertical shear and favorable divergence aloft. The Darwin TCWC began issuing advices on the developing system at 0630 UTC on 17 December, placing the center then about 250 nm west of Darwin. Deep convective banding wrapping into the center had developed by the 18th and JTWC issued a TCFA for the LOW. At 18/1200 UTC BoM Darwin named the system Tropical Cyclone Billy with 40-kt winds. Billy was moving slowly southeastward toward the Kimberley coast from a position about 200 nm southwest of Darwin. The cyclone continued to strengthen, reaching an initial peak intensity of 50 kts at 19/0600 UTC. This made Billy a Category 2 cyclone on the Australian Cyclone Severity Scale. Later on the 19th the cyclone's motion became west-southwesterly with the center crossing the coastline north of Wyndham around 1800 UTC. Following landfall, Billy weakened and was downgraded to a tropical LOW at 20/0600 UTC. Over the next couple of days ex-Billy moved toward the west just inland from the Western Australia coastline, maintaining its structure, as inland cyclones tend to do in Australia. The LOW moved back out over water around 0000 UTC 22 December and was immediately re-upgraded to cyclone status. Billy turned to the west-southwest and continued to hug the coastline for a couple of days, which slowed the re-intensification process. Late on the 23rd, Billy began to rapidly intensify with the MSW (10-min avg) increasing from 45 kts to a peak of 95 kts in 24 hours. The cyclone reached its peak intensity of 95 kts at 1800 UTC on Christmas Eve while located approximately 170 nm north- northwest of Port Hedland. (JTWC's concurrent 1-min avg MSW was 105 kts, in good agreement with BoM Perth.) Around 24/0000 UTC Billy displayed a 6-nm diameter pinhole eye. Around the time Billy peaked in intensity, its track took on a rather pronounced west-northwesterly component. The cyclone's intensity held rather steady through Christmas Day, but began to decline thereafter as vertical shear increased significantly. The storm dropped below hurricane intensity at 26/1800 UTC, and the Perth TCWC issued their final warning at 28/1200 UTC as Billy weakened into a tropical LOW about 380 nm north-northwest of Onslow, Western Australia. The remnants of Billy moved generally westward for another couple of days. In the companion cyclone tracks file prepared by the author, the track following Perth's final bulletin is based upon SAB satellite fix bulletins. I lowered the winds to 25 kts based upon these, but a 29/1011 UTC QuikScat pass showed some 30-kt wind vectors; also, there was some renewed convection and SAB assigned a T2.0/2.0 Dvorak rating at 29/0830, so I raised the MSW to 30 kts for that time only. Following this the LOW continued to weaken and the final SAB bulletin placed the very weak center about 400 nm south-southeast of Christmas Island at 30/0830 UTC. The remnants of former Tropical Cyclone Billy continued moving westward across longitude 90E and several days later were in close proximity to another disturbance which developed into Severe Tropical Storm Dongo in early January. According to the Wikipedia report, two remote indigenous communities, Kalumburu and Oombulgurri, were cut off by floodwaters with roads and the airstrips closed. No other information regarding damage and/or casualties has been received. (Report written by Gary Padgett) ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for December: No tropical cyclones ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for December: 1 tropical depression South Pacific Tropical Activity for December -------------------------------------------- RSMC Nadi issued bulletins on three numbered disturbances during the month of December, classifying one of them as a tropical depression. Tropical Disturbances 01F and 03F were very short-lived and weak: 01F formed on 1 December near the Northern Cooks and lasted only a couple of days as it drifted westward, and 03F formed on 10 December in the Solomon Islands area. This system apparently had no definite LLCC and all the convection was confined to the north of the system. The second system, 02F, formed on 3 December near the Southern Cooks and moved to the south- west for a few days. It became organized enough that Fiji upped its classification to depression status on the 5th, but central winds never exceeded 25 kts. I did not prepare a track for this system as it was quite weak, but track graphics and some information may be found for all three of these disturbances on the Wikipedia website. ************************************************************************* SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION The purpose of this section is to list some websites where many and varied types of tropical cyclone information are archived. Many readers will know about these already, but for the benefit of those who don't, I wanted to include them. (1) Aircraft Reconnaissance Information --------------------------------------- Various types of messages from reconnaissance aircraft may be retrieved from the following FTP site: Information regarding how to interpret the coded reconnaissance messages may be found at the following URL: Links are also included to websites with further information about the U. S. Air Force 53rd Weather Reconnaissance Squadron and the NOAA Air- craft Operations Center. (2) Archived Advisories ----------------------- All the advisory products (public advisories, forecast/advisories, strike probabilities, discussions, various graphics) issued by TPC/NHC are archived on TPC's website. For the current year (using 2004 as an example), the archived products can be found at: Links to tropical products archives for earlier years are available at the following URL: JTWC warnings for past storms are archived on the NRL Monterrey website: On the NRL site, the link to past years can be found in the upper left corner of the screen. I am not aware at the moment of any other TCWC which archives all its tropical cyclone warning/advisory products for public access, but if I learn of any, I will add them to this list. (3) Satellite Imagery --------------------- Satellite images of tropical cyclones in various sensor bands are available on the NRL Monterrey and University of Wisconsin websites, courtesy of Jeff Hawkins and Chris Velden and their associates. The links are: On the NRL site, the link to past years can be found in the upper left corner of the screen. For the CIMSS site, a link to data archives is located in the lower left portion of the screen. Additional tropical satellite imagery, along with looping ability for composite microwave imagery for the Western Hemisphere north of the equator, can be found at: (1) For the Eastern North Pacific: (2) For the Atlantic, Gulf of Mexico and Caribbean Sea: (4) Cyclone Tracking Information -------------------------------- There is a U. S. Navy site that tracks tropical cyclones at 6-hourly intervals which often includes pre and post-advisory positions. The link to the site is: Steve Young has compiled many of these tracks onto a single webpage which is very user-friendly: I'm sure there are other sites with available imagery available, and as I learn of them, I will add the links to this list. ************************************************************************* EXTRA FEATURE In order to shorten the amount of typing in preparing the narrative material, I have been in the habit of freely using abbreviations and acronyms. I have tried to define most of these with the first usage in a given summary, but I may have missed one now and then. Most of these are probably understood by a majority of readers but perhaps a few aren't clear to some. To remedy this I developed a Glossary of Abbreviations and Acronyms which I first included in the August, 1998 summary. I don't normally include the Glossary in most months in order to help keep them from being too long. If anyone would like to receive a copy of the Glossary, please e-mail me and I'll be happy to send them a copy. ************************************************************************* AUTHOR'S NOTE: This summary should be considered a very preliminary overview of the tropical cyclones that occur in each month. The cyclone tracks (provided separately) will generally be based upon operational warnings issued by the various tropical cyclone warning centers. The information contained therein may differ somewhat from the tracking and intensity information obtained from a "best-track" file which is based on a detailed post-seasonal analysis of all available data. Information on where to find official "best-track" files from the various warning centers will be passed along from time to time. The track files are not being sent via e-mail. They can be retrieved from the archive sites listed below. (Note: I do have a limited e-mail distribution list for the track files. If anyone wishes to receive these via e-mail, please send me a message.) Both the summaries and the track files are standard text files created in DOS editor. Download to disk and use a viewer such as Notepad or DOS editor to view the files. The first summary in this series covered the month of October, 1997. Back issues can be obtained from the following websites (courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and Chris Landsea): Another website where much information about tropical cyclones may be found is the website for the UK Meteorological Office. Their site contains a lot of statistical information about tropical cyclones globally on a monthly basis. The URL is: TROPICAL CYCLONE REPORTS AVAILABLE JTWC now has available on its website the Annual Tropical Cyclone Report (ATCR) for 2007 (2006-2007 season for the Southern Hemisphere). ATCRs for earlier years are available also. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2007 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2007 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. PREPARED BY Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 Kevin Boyle (Northwest Pacific) E-mail: newchapelobservatory@btinternet.com ************************************************************************* ************************************************************************* Posted: 03.11.09 / Typhoon2000.ph, Typhoon2000.com